Muffled vibrator



April 2, 1957 J. E. BECKER 2,787,251

MUFFLED VIBRATOR Filed Feb. s, 1955 IN1 'ENToR. dal/les E. Becker BY g.4 @fd/277% @MM 27M /4 TfOR/VL'YS railroad hopper cars, bins, and chutes.

United States Patent() MUFFLED. VIBRATOR JamesE. Becker, Rocky River,VOhio Application February..8,1955,-SerialNo. 486320 2 Claims. (Cl.121-17)` The invention relates to industrial vibrators such `as areused, for example, to facilitate discharge of granulated or nondescriptcomminuted material from sloping walled containers, such as discharge ofsand or slag from Other familiar uses are, for example, vibrationtables, foundry shakeouts, pneumatic hammers or the like.

As is familiar to those skilled in related arts of this type, a vibratorusually operates on a principle involving rapid reciprocati'on, orperhaps off-center rotation, of a movable element within a housing, saidhousing being bolted or otherwise irmly attached to the article whichmust be Vibrateds such as the cope of a mold or the body of the bin orhopper car. Compressed air is the usual motive power for the vibrator,and the exhaust air normally escapes to atmosphere, the resulting airdisturbance causing loud, and harsh noises, the pitch of coursedepending on the frequency of successive exhaust discharges. In anenclosed space such as a factory or workshop, or when attached lto asteel walled hopper or other container, the resultant noise can be mostirritating to anyone in the vicinity. The ordinary pedestrian has beensubjected to the disturbing eiect created by the use of pneumatichammers by pavement workers.

An object of the present invention is to provide a pneumatic power toolof the vibrator type wherein the exhaust discharge noise is reducedalmost to an imperceptible level, certainly to a non-irritating level,without reducing the efficiency of the vibrator.

Another object of the invention is to provide a vibrator of the typedefined in the last preceding paragraph which can be manufactured at acost not substantially exceeding the cost of a conventional non-muledvibrator.

Other objects and advantages will be apparent from a study of thefollowing description of several embodiments of the invention, inconjunction with the accompanying drawings, in which:

Fig. 1 is a sectional View .taken axially on a vibrator embodying myinvention.

Fig. 2 is a view partly in plan and partly in section, showing aslightly modified form of my invention.

Fig. 3 is a View similar to Fig 2 but showing yet another embodiment ofthe invention.

Fig. 4 is an enlarged view showing a structural detail of part of theapparatus shown in Fig. 3.

Referring rst to Fig. 1, there is shown a housing of tubular characterand of sturdy construction having ra bored aperture 11 Itherethrough,the aperture being closed at both ends by end plates 12 and 13 which areheld in tight, leak-proof contact with the body by tie bolts 14. The tiebolts can pass outside the body, as indicated in the embodiments ofFigs. 2 and 3, passing between lugs in the end plates which clear thebody portion 1i). Obviously the end plates could be held in place bystuds threaded into rtapped apertures in the body, although the method Ishow avoids the necessity of drilling and tapping the body ends.

A reciprocable member, or piston 15 has a slidable it within boreV 11and ithastwo annular peripheral grooves 1'6 and 17, groove 16` havingiiuid ll'owA communication with Ithe piston end 15a through passage 16a,and; groove 17 being` in communication with the piston' end 15b throughpassage 17a thereby providing access to endhead chambers 18 and 19.

A bored exhaust passage, 20 extends' longitudinally througlithe bodywall, and it has two portsl 2T and 22 communicating with respectiveopposedj end chambers 18 and' 1'9'. EndE plate 13 hasexhaust ports 23establishingv communication` between. exhaust `passage 20" andt at'-nrosphere. Spaced from exhaust passage 20`tlie' bodywall has an airinlet port 24 located centrally to permit periodic registry with eithergroove 16 or groove 17 on the piston 15. To facilitate proper operation,as described immediately hereinafter, the inner body wall has an annulargroove 25 in registry with port 24. Exhaust passage 20 is packed withpermeable material such as bronze wool 27, or any sound deadeningmaterial.

In operation the device functions as follows. In the position shown inFig. 1, grooves 16 and 25 are in registry. If compressed air is admittedthrough port 24, it will pass through passage 16a to end chamber 1S,whereupon piston 15 is thrown towards the left end. This movementquickly interrupts communication between port 24 and passage 16a but thepiston continues its movement (chamber 19 being still vented throughoutlets 22, 2i), and 23 in succession) until piston end 15a clearsoutlet 21 at which time chamber 18 is vented to exhaust through 21, 20,and 23, tand passage 22 is closed by piston end 15b. At this stagecompression of residual air in chamber begins to impede the movement ofpiston 15, and about the same time groove 17 comes to registry withgroove 25 and port 24 thereby admitting compressed air through passage17a to chamber 19, reversing the piston motion and completing a cycle.All this of course takes place with great rapidity. In this design thepiston never comes to actual contact with either plate 12 or 13.

It will be observed that the exhaust air, from chambers 18 and 19alternately, passes through respective passages 21 and 22, and thenthrough the permeable material 27 before passing outwardly through vents23 to atmosphere. l have found that the provision of the muling passage20 very materially quiets the operation of the vibrator so that itbecomes actually unnoticeable except for 'a slight hissing noise7 andthere is no sensation of motor boating, or no siren-like noise, theselatter two phenomena being exempliiications lof low or high fre quencyexhaust discharges. The invention of course is not limited to vibratorsof the type just mentioned, but can also be utilized in connection withrotary type vibrators in which the exhaust is practically continuous.

In the embodiment of ig. l, it will be noted that the ultimate dischargeis Iall through the right end so that the alternate discharges fromchambers 18 and 19 pass through respectively varying amounts of mufingmaterial. In the embodiment illustrated in Fig. 2, the ports 28 havebeen drilled centrally of the length of the exhaust passage 20a, so thatair escaping from either of the end chambers of the cylinder tnavelsthrough approximately the same amount of mui'lling material.

Figs. 3 and 4 show another embodiment wherein the exhaust chamber 20bhas a conventional type of muffler inserted therein. Any typeofnoise-muflling device will be satisfactory las long as it is adaptable'to the somewhat limited space requirements of the exhaust passage 2012.

Merely as an illustration, I show several concentric tubes` 29 and 30,spaced from each other and from the exhaust passage wall. The tubes havea plurality of perforations 31 therethrough, and there are annularspacers 32 which 3 serve to baffle air flow and maintain the spacing ofthe tubes. This type of muffler can be manufactured separately andinserted endwise into chamber 20b. Air emerging from port 33, forexample, must travel through a circuitous course before exhausting toatmosphere through vents 34, while undergoing successive expansions.

What I claim is:

1. Vibrator means of the character described compris ing an elongatedbody having an axial aperture therein, an inlet port to each end `ofsaid aperture from the body exterior, a second aperture in the body wallgenerally paral- Ilel to said lirst aperture, and having an opening toatmosphere, a pair of exhaust ports, one from each of the opposite endsof said iirst aperture and opening into sai'd second aperture, saidsecond aperture being filled with noise muting material, and an elementin said irst aperture rapidly reciprooable responsive to admission ofpressure uid to said inlet port.

2. Vibrator means as defined in claim l wherein the opening toatmosphere from said second aperture is substantially evenly spacedfrom, and between, said exhaust ports whereby the exhaust from each endof the said first aperture travels approximately an equal distancethrough said noise muling material.

References Cited in the file of this patent UNITED STATES PATENTS2,073,480 Jimerson Mar. 9, 1937 2,516,949 Bourne Aug. 1, 1950 2,590,155Cannon Mar. 25, 1952 2,678,637 Doeden May 18, 1954

